Highway construction and engineering includes planning, designing, and building of highways. History stands witness that good roads lead to prosperity for distant societies. If a road is well planned and then executed according to the plan, a highway can open the gates of growth and development. Highways connect two or more places and ensure that…
Introduction A priority intersection occurs between two roads, one termed the ‘major’ road and the other the ‘minor’ road. The major road is the one assigned a permanent priority of traffic movement over that of the minor road. The minor road must give priority to the major road with traffic from it only entering the…
Introduction A highway intersection is required to control conflicting and merging streams of traffic so that delay is minimised. This is achieved through choice of geometric parameters that control and regulate the vehicle paths through the intersection. These determine priority so that all movements take place with safety. The three main types of junction dealt…
Introduction ‘Level of service’ describes in a qualitative way the operational conditions for traffic from the viewpoint of the road user. It gauges the level of congestion on a highway in terms of variables such as travel time and traffic speed. The Highway Capacity Manual in the US (TRB, 1985) lists six levels of service…
In a situation where only one car is travelling along a stretch of highway, densities (in vehicles per kilometre) will by definition be near to zero and the speed at which the car can be driven is determined solely by the geometric design and layout of the road; such a speed is termed free-flow speed…
Introduction It is proposed to upgrade an existing single carriageway road to a dual carriageway and to improve some of the junctions. The time frame for construction of the scheme is set at two years, with the benefits of the scheme accruing to the road users at the start of the third year. As listed…
Once the two parameters of project life and discount rate are set in place, these allow all costs and benefits to be directly compared at the same point in time. The decision-maker must now choose the actual mechanism for comparing and analysing the costs and benefits in order to arrive at a final answer for…
A highway project is often complex and long term, with the costs and benefits associated with it occurring over a long time frame which we term the life of the project, a parameter dealt with in earlier chapters. It sets a limit on the period over which the costs and benefits are estimated, as all…
The application of cost-benefit for project assessment in the highway area is made more complicated by the wide array of benefits associated with a given road initiative, some easier to translate into monetary values than others. Many of the benefits of improvements to transport projects equate to decreases in cost. The primary grouping that contains…
Introduction Within Europe, the method usually adopted for the economic evaluation of highway schemes, termed cost-benefit analysis, utilises the net present value technique where the costs and benefits of the scheme are discounted over time so that they represent present day values. Using this method, any proposal having a positive net present value is economically…